IDH1 and glioma: Accumulation of 2HG to high levels in tumors can cause metabolic and non-metabolic dysregulation and malignant transformation.15 Unlike IDH-mutant leukemias whose increased 2HG may be found in the blood, IDH-mutant gliomas have normal blood levels and efforts to detect 2HG have thus far centered on imaging predominantly with proton magnetic resonance spectroscopy (MRS).